Ok for fun:
March 1917, the Allies deperate to cutrail the German submarine offensive and to open communications to a still Allied Russia offer Denmark secretly a slice of Germany including the Kiel Canal and 30 miles past, part of the German colonial empire post war, a share of the captured German naval booty and military equipment post war and a considerable annual subsidy for 50 years.
The Danes agree to enter the war if and when the Americans do and once the French launch their Nivelle offensive, and so on April 22nd, allied Naval Flotillas move into Copenahgen bringing along a British and a French Division.
The shock of all this plus the Greek declaration of war, the fall of Baghdad etc. causes Ludendorf to have a breakdown, the Kiaser to abdicate, the Crown Prince takes over and Germany agrees to end the war under terms of loss of Alcase Lorraine and her colonies, and her fleet, and the OTL 1919 boundy of Denmark (faced with a German invasion the Danes are happy to take only this part of Germany).